only 2 questions ...

1. what is it ?

2. Is there anyway to spot an engine with it ?


From some searching around I have found it's something to do with valve overlap and is supposed to lower fuel consumption. Since I have a genetically heavy right foot, I can't say I have noticed any drastic difference in economy ( or lack of it ) between my old MY01 WRX ( no avcs ) and my 2001 Forester S/tb ( with avcs ).

Does it provide any other benefits ?


Cheers
Steve

It stands for active valve control system (IIRC), and is, unsurprisingly, a variable valve timing system.

As for which engines have it, the new age STi engines do.

do the newage UK spec STI's have them, how is it controlled, can you have aftermarket cams with this system, is there any point??

Taken from the MY'06 Tech Manual :


http://img.photobucket.com/albums/v4..._explained.jpg



If you do a internet search for AVCS - be aware that some of the cams listed on various sites are for USDM "twin cam" EJ series and not the quad cam.

Mick

thanks merlin
Im trying to find out as i have a classic engine i want to put in a newage 03 uk sti and I have been told this makes it impossible..i cant see how or why.....anyone know??

VVT will help with spool up and other power related positives as regards to cam timing.

I run after market CAMS in my Newage VVT engine.

If retro-fitting, you would obviously need an ECU that can control VVT as well as the appropriate loom.

Steve I would check carefully I doubt your JDM has AVCS as the engine is carried on from the earlier cars, no EU cars had AVCS and central coil pack (we've had that 'what MY is your car' chat before!), and EDM 01 Foz didn't have AVCS either.

Its used for fuel economy - increasing overlap reduces pumping losses at part throttle - by about 5%, reducing lag/improving off boost torque and reducing emissions (increased overlap increases internal EGR and the heat helps atomisation of fuel after a cold start).

I would say retrofitting it would cost a lot more than you will ever save, your looking at a complete engine swap and loom and ECU!

Simon